public class Rational {
   int numerator = 1 ;   //分子
   int denominator = 1; //分母
   void setNumerator(int a) {  //设置分子
      int c=f(Math.abs(a),denominator);  //计算最大公约数
      numerator = a/c; 
      denominator = denominator/c;
      if(numerator<0&&denominator<0) {
          numerator = -numerator;
          denominator = -denominator;
      }
   }
   void setDenominator(int b) {  //设置分母
      int c=f(numerator,Math.abs(b));  //计算最大公约数
      numerator = numerator/c;
      denominator = b/c;
      if(numerator<0&&denominator<0) {
          numerator = -numerator;
          denominator = -denominator;
      }
   }
   int getNumerator() {
      return numerator;
   }
   int getDenominator() {
     return denominator;
   }  
   int f(int a,int b) { //求a和b的最大公约数
      if(a==0) return 1;
      if(a<b) {
         int c=a;
         a=b;
         b=c; 
      }
      int r=a%b;
      while(r!=0) {
         a=b;
         b=r;
         r=a%b;
      } 
      return b;
   }
   Rational add(Rational r) {  //加法运算
      int a=r.getNumerator();
      int b=r.getDenominator();
      int newNumerator=numerator*b+denominator*a; //计算出新分子
      int newDenominator=denominator*b;           //计算出新分母
      Rational result=new Rational(); 
      result.setNumerator(newNumerator);
      result.setDenominator(newDenominator);
      return result;
   }
   Rational sub(Rational r) {  //减法运算
      int a=r.getNumerator();
      int b=r.getDenominator();
      int newNumerator=numerator*b-denominator*a;
      int newDenominator=denominator*b;
      Rational result=new Rational(); 
      result.setNumerator(newNumerator);
      result.setDenominator(newDenominator);
      return result;
   }
   Rational muti(Rational r) { //乘法运算
      int a=r.getNumerator();
      int b=r.getDenominator();
      int newNumerator=numerator*a;
      int newDenominator=denominator*b;
      Rational result=new Rational(); 
      result.setNumerator(newNumerator);
      result.setDenominator(newDenominator);
      return result;
   }
   Rational div(Rational r)  { //除法运算
      int a=r.getNumerator();
      int b=r.getDenominator();
      int newNumerator=numerator*b;
      int newDenominator=denominator*a;
      Rational result=new Rational(); 
      result.setNumerator(newNumerator);
      result.setDenominator(newDenominator);
      return result;
   }
}






